The purpose of this study was mainly to explore the role and mechanism of microRNA-18a-5p (miR-18a-5p) in oral squamous cell carcinoma (OSCC). The expression of miR-18a-5p in OSCC cells and normal cells was firstly detected using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The cell viability, apoptosis, migration and invasion abilities of OSCC cells were determined by MTT, cell apoptosis, wound healing and Transwell assays respectively. Additionally, bioinformatics software analysis and luciferase reporter assays were performed to predict and confirm the candidate target of miR-18a-5p. Western blot analysis was used to assess protein expression. It was revealed that the expression of miR-18a-5p in OSCC cells was higher than that in normal cells. In vitro studies revealed that the cell viability, migration and invasion abilities of OSCC cells were promoted and cell apoptosis was inhibited by miR-18a-5p overexpression. In addition, Smad2 was identified as a target of miR-18a-5p. It was also revealed that miR-18a-5p overexpression significantly inhibited the expression of Smad2, Smad4 and E-cadherin, and the levels of Smad7, collagen I, transforming growth factor-β (TGF-β), α-smooth muscle actin (α-SMA), vimentin were enhanced. While miR-18a-5p downregulation presented the opposite effects. In conclusion, the results indicated that miR-18a-5p can regulate the biological process of OSCC by targeting Smad2 and miR-18a-5p/Smad2 may be potential therapeutic targets for OSCC.

Background: Intra-articular disorders (ID) or anterior and/or medial displacement of the temporomandibular joint disorder (TMJ) disc are the most common form of TMJ dysfunction (TMD). TMD causes changes in the friction coefficient during TMJ movement. Herein, we provided a three-dimensional (3D) finite-elements model (FEM) including the maxilla, disc, and mandible and evaluated the stress distribution with different friction coefficient. Methods: Fourteen volunteers without TMD and 20 patients with MRI-diagnosed TMD were selected. CT and MRI data were collected to build the 3D FEA model of the mandible and TMJ disc. Stress distribution with different friction coefficient was measured. Result: In the normal model, stress distribution on the TMJ disc was 2.07 ± 0.17, 1.49 ± 0.14, and 1.41 ± 0.14 MPa with 0.001, 0.3, and 0.4 friction coefficient, respectively. In the TMD model, stress distribution was 3.87 ± 0.15, 7.23 ± 0.22, and 7.77 ± 0.19 MPa respectively. Conclusion: When the friction coefficient of the side with anterior displacement increased, stress on the disc, condyle and mandible of the opposite side increased. Simultaneously, stress values of the disc, condyle and mandible were higher than those of the normal lateral joint.

Background：Anterior and/or medial displacement of the temporomandibular joint disorder(TMJ) disc or intra-articular disorders( ID) is the most common form of TMJ dysfunction(TMD).TMD cause change of friction coefficient during TMJ movement. In the present study, We provided a 3D finite elements models(FEM) including the maxilla, disc and mandible and evaluated the stress distribution with different friction coefficient.Methods: 14 volunteers without TMD and 20 TMD patients,who were diagnosed by MRI, were selected.CT and MRI data were collected to build 3D FEA model of mandibular and TMJ disc.Stress distribution with different friction coefficient was measured.Result: In the normal model, stress distribution on TMJ disc was 2.07±0.17,1.49±0.14,1.41±0.14MPa with 0.001 0.3 and 0.4 friction coefficient.In TMD model,stress distribution is 3.87±0.15,7.23±0.22,7.77±0.19MPa respectively. Conclusion:When the friction coefficient of the side with anterior displacement increased, stress on the disc, condyle and mandible of the opposite side increased. Simultaneously, stress values of the disc, condyle and mandible were higher than those of the normal lateral joint.

Background： Anterior and/or medial displacement of the articular disc or intra-articular disorders( ID) is the most common form of TMJ dysfunction.In the present study,3D finite elements analysis (FEA) models including the maxilla, disc and mandible were established using 3D data registration technology. Materials and Methods： Six healthy volunteers and 20 TMD patients were selected.CT and MRI data were collected to build 3D FEA model of mandibular and TMJ disc. Result: Results showed that maximum stress of the normal lateral articular disc in the normal and pathological models appeared in the lateral part of the middle band. In the normal model, stress distribution was more uniform and the joint disc and the condyle were also subjected to higher load at the junction of the articular disc and the condyle. Conclusion: When the friction coefficient of the side with anterior displacement increased, stress on the disc, condyle and mandible of the opposite side increased. Simultaneously, stress values of the disc, condyle and mandible were cd32fvhigher than those of the normal lateral joint.